Touch Panel Module with Lambda Quarter Plate for Low Reflectivity
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Solution Overview
Problem
Touch panels with mesh-like metal electrodes face issues of high visibility and reduced image quality due to line visibility and screen contrast problems, particularly when compared to transparent conductive materials like ITO, which are not suitable for large screens.
Innovation Solution
A touch panel module configuration is developed with a mesh conductive layer on a support, a λ/4 plate, a polarizing plate, and a protective layer, where the visible light diffuse reflectivity is 0.2% or less, and the L* value of the surface is 2 or less, along with a low equilibrium moisture content in the λ/4 plate, to minimize the visibility of the mesh-like metal electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mesh-like metal electrode is used for the touch panel, then the electrical resistance is reduced and suitability for large screens is improved, but the visibility of the electrode (line visibility) increases and image quality deteriorates
Solution Approach 1:
The patent applies a circularly polarizing plate with specific reflectivity characteristics (0% ≤ |R0(λ1)−R0(λ2)| ≤ 0.5%) to suppress the visibility of the mesh-like metal electrode. By controlling the front surface reflectivity across different wavelengths, the electrode becomes less visible while maintaining its low electrical resistance properties, thus resolving the contradiction between electrical performance and visual quality.
Solution Approach 2:
The patent combines the mesh-like metal electrode with a circularly polarizing plate consisting of multiple layers (front reflection suppression layer, polarizer, and λ/4 plate). This composite structure allows the metal electrode to maintain its low resistance while the polarizing plate suppresses its visibility, effectively resolving the contradiction between electrical conductivity and aesthetic appearance.
2Object-affected harmful factors
If a transparent conductive material such as ITO is used for the touch panel, then the line visibility is suppressed and image quality is improved, but the electrical resistance increases and suitability for large screens deteriorates
Solution Approach 1:
The circularly polarizing plate with controlled reflectivity characteristics suppresses the visibility of the mesh-like metal electrode by manipulating light reflection properties across different wavelengths, achieving image quality comparable to transparent conductive materials while maintaining the electrical advantages of metal electrodes.
Solution Approach 2:
The circularly polarizing plate acts as an intermediary layer between the viewer and the mesh-like metal electrode. It mediates the visual appearance by suppressing the electrode's visibility while allowing the electrode to maintain its low electrical resistance, thus bridging the gap between aesthetic requirements and electrical performance.
3Reliability
If the mesh-like metal electrode is made more visible to ensure electrode function, then the electrical performance is maintained, but the screen contrast is lowered and image quality becomes poor
Solution Approach 1:
The circularly polarizing plate with specific reflectivity characteristics suppresses the visibility of the mesh-like metal electrode, preventing it from lowering screen contrast. The electrode maintains its functional electrical performance while the polarizing plate ensures that the screen contrast and image quality remain high by controlling light reflection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces the visibility of the mesh-like metal electrode, maintaining low resistance and improving image quality by suppressing line visibility and migration issues, while allowing for a touch panel module suitable for large screens.
Implementation Method 1
a λ/4 plate, a polarizing plate, and a protective layer are arranged in this order
Implementation Method 2
the visible light diffuse reflectivity thereof measured from the protective layer is 0.2% or less
Data Source
AI summary
A touch panel module in which a conductive film in which a mesh conductive layer composed of a mesh-like metal electrode is formed on a support, a λ/4 plate, a polarizing plate, and a protective layer are arranged in this order. A λ/4 plate is further arranged on a side of the conductive film opposite to the protective layer. The touch panel module has a visible light diffuse reflectivity of 2% or less, which is measured from the protective layer.